Most of the southwestern United States is having a very dry winter. The northern parts of Arizona and New Mexico were clipped by a few drenching storms exiting California in December, but dry conditions are more the norm. According to the latest report on precipitation from the NOAA-sponsored Climate Assessment for the Southwest project, “In January, nearly all of Arizona and New Mexico received less than 5 percent of the historical average.”
In many parts of Arizona, New Mexico, and western Texas, precipitation was more than 50 percent below normal as of February 8, 2011. In the Southwest, the new “water year” begins on October 1. Precipitation data from the NOAA/NWS Advanced Hydrologic Prediction Service.
The map above shows the difference from normal precipitation received in the Southwest between the beginning of the water year on October 1, 2010, and February 8, 2011. Areas with less-than-normal precipitation (negative percents) are shades of orange and red, areas with near-normal rainfall are yellowish white, and areas where precipitation was above normal are blue.
The next post in this series will explain patterns of rainfall in the Southwest, the influence of El Niño and La Niña, and some of the implications of a dry winter on water supplies and natural resources.